Liquid analysis apparatus with closed flow cell



Nov. 5, 1963 A. FERRARI ETAL 3,109,713

LIQUID ANALYSIS APPARATUS WITH CLSED FLOW CELL Filed July 12. 1960 Cocomere I4 j @eL-opor? /6/ IN V EN TORS Annees :qe-44mg JAcK [Spera United States Patent O 3,109,713 LIQUID ANALYSIS APPARATUS WITH CLOSED FLOW CELL Andres Ferrari, Scarsdale, and Jack Isreeli, Tuckahoe, N.Y., assgnors to Technicon Instruments Corporation, Chauncey, N.Y., a corporation of ANew York Filed July 12, 1960, Ser. No. 42,258 5 Claims. (Cl. 23-253) The present invention relates to automatic analysis apparatus and, more particularly, -to such apparatus which includes a closed flow cell of a colorimeter for the colorimetric analysis of a liquid stream to quantitatively determine a constituent thereof. The apparatus may be used for analyzing a series of individual samples or may be used `for monotoring a system continuously, for example, a steam power plant on a ship.

The invention is especially useful 4in its application to automatic continuous analysis apparatus of the type described, for example, in United States Patent No. 2,797,- 149, of the assignee of the present application, wherein streams of fluid .are transmitted through small tubular passages which are provided in such apparatus. As explained in said patent, air is introduced into the liquid streams lto divide them into a series of successive small segments separated from each other by intervening air segments or bubbles which serve to cleanse the internal walls of the passages. Where a series of samples are being analyzed, air is also introduced between successive samples of the liquids to separate the samples from each other and to provide a cleansing action of the passages between successive samples in order to prevent contamination of one sample by another, which might otherwise occur due to the fact that the samples are introduced into the passages in series one after the other in a tlowing stream.

At a predetermined stage in the operation of the apparatus, it is necessary to abstract the air or other inert fluid introduced into the liquid streams in order to consolidate and blend the liquid segments of the processed liquid into a continuous liquid stream for nal examination in a colorimeter of the ow cell type, as described in the above mentioned patent.

`Where the apparatus is being employed to monitor, for example, the chlorine content in the boiler feed water of a steam power plant which is installed aboard a ship, it is necessary that the apparatus be in a closed system so that the pitching, rolling and yawing of the ship does not cause any spilling of the liquids in the system and, therefore, the flow cell of the colorimeter must be of the closed or non-vented type. In accordance with the present invention and pursuant to one of the objects thereof, the air or other inert separable tluid introdu-ced into the liquid stream is removed prior to its introduction into the llow cell of the colorimeter.

In accordance with another object of the invention, a blender is provided in the path of llow of the liquid segments so that they are consolidated into a continuous liquid stream for flow through the tlow cell for proper operation of the colorimeter and a colorimeter controlled recorder.

The above and other objects, features and advantages of the invention will be fully understood from the following description considered in connection with the accompanying il-lustrative drawings.

In the drawings:

FIG. l is a more or less diagrammatic view illustrating the apparatus according to the present invention; and

FIG. 2 is a view of part of the apparatus of FIG. l, on a larger scale, partly in section and partly in perspective.

Referring now to the drawings in detail, the apparatus comprises a proportioning pump 12 which has pro- 3,109,713 Patented Nov. 5, 1963 ice vision for pumping a plurality of fluids for the continuous treatment of a liquid stream for colorimetric analysis. 'IThe treated stream is colorimetrically analyzed in the colorimeter 14 which operates a recorder 16, in a well known manner, to record the results of the colorimetric analysis.

The ow of cell 18 of the colorimeter is in the form of a hollow cylinder and has transparent end walls 20 and 22 which are therefore permeable to light and through which a beam of light 24 passes for the colorimetric examination of the liquid in the ow cell. It will be understood that :light beam Z4 comes from a suitable light source (not shown) and is absorbed in accordance with the light transmittance qualities of the liquid. The degree of absorption of the light by the liquid is measured by a photoelectric device (not shown) which is placed in the path of the light beam which passes through end wall 22 of the llow cell.

The ow cell includes the tubular members or nipples 26 and 28 which provide a liquid inlet and a liquid outlet, respectively, for the flow of liquid into and out of the ilow cell. Except for the liquid inlet and liquid outlet, the How cell is completely closed and does not include any vent openings. Accordingly, such a ow cell may be placed an any of a plurality of positions without any spilling occurring of the liquid through an opening in the ow cel-l. This is especially advantageous when the flow cell is used in an analysis apparatus or system which may be aboard a ship or other moving vehicle and the pitching, rolling and yawing of the vehicle will not cause any spilling of the liquid in the liow cell.

As ilustrated in FIG. 2, the fluid stream as it flows through a tube or conduit 30 from the pump 12 is composed of segments of liquid L and intervening segments G of air, which is introduced into the stream of the liquid under analysis at iitting 32 where ythe stream of liquid flowing in tube or conduit 34 joins the stream of air flowing in conduit or tube 36. The liquid under analysis Y is introduced into the system by way of pump tube 38 and the air is introduced into the system by way of pump tube 40. It will be understood that in lieu of air any other suitable inert separable fluid may be used to divide the liquid stream into alternate segments of liquid separated from each other by intervening segments of fluid. The segmented stream flows from the outlet of the fitting 32 through a Itube or conduit 42 where it joins a stream of processing liquid or color reagent tlowing in conduit 44. The processing liquids are introduced into the system by way of pump tubes 46 and 48 and flow through conduits or tubes 50 and 52, respectively, to fitting 54 where they join each other and are mixed together in helical mixing coil 56. The segmented stream consisting of liquid segments containing sample and processing liquid or reagent separated by intervening segments of air is transmitted by the action of the pump through conduit or tube 58 to a helical mixing coil 60, where the liquids in each of the liquid segments L are mixed with each other.

The outlet end of mixing coil 60 is connected to conduit 30 which transmits the segemented stream to a tting or separating device 62 which is positioned at a point upstream of the inlet to the flow cell and removes and separates lthe air segments of the stream from lthe liquid segments. The itting 62 comprises tubular inlet part 64, tubular outlet part 66 and tubular oitake par-t 68 which is intermediate the inlet land outlet par-ts of the iitting and is connected by a conduit 70 to lthe pump tube72. When the segmented stream enters inlet part 64, the air segments or bubbles G are separated from the segmented stream by the aspirating action of the pump an-d ow through opening 74 in fitting 62 into ofltake part 68 and conduit 70, along with small quantities of the liquid segments,

while liquid free of air and inthe form of 4a liquid stream flows from outlet part 66 of the fitting to the flow cell 18.

. Disposed between fitting 62 and the flow cell is a blender device 76, preferably made of glass, which assists in the blending of the individual liquid segments into a continuous consolidated stream of liquid. The blender device is a tubular member consisting of a series of spherical hollow parts 78 separated from each other lengthwise of the path of flow of the stream by a series of intervening tubular connecting parts 80. Because of the different cross sectional areas of the spherical parts 78 and the tubular parts 80, the liquid segments alternately and continuously change their velocities as they flow successively Ithrough the spherical parts and tubular parts, which results in a thorough blending of adjacent liquid segments with each other, so that a consolidated liquid stream flows to the inlet 26 of the flow cell, which is connected to the outlet end of the blender 76. It will be understood that it is within the scope of the present invention to use other lblender means for the liquid segment, for example the helical mixing coil shown in U.S. Patent No. 2,933,293 which is owned -by the assignee of the present invention.

The total volume of fluid aspirated from fitting 62 lthrough offtake part 68 is less th-an the total volume of fluid entering the fitting through inlet part 64. The difference in the volumes of the fluids is continuously transmitted to the flow cell 18 through the blender 76 and the inlet 26 of the flow cell and' after passing through the flow cell is discharged through outlet 28. It will be understood that outlet 28 of the flow cell preferably extends to a discharge position remote from the colori-meter 14. In addition, Outlet 28 is preferably so arranged that a part thereof (not shown) extends higher than the flow cell so that the flow cell is completely filled with liquid at all times. Other means, for example a valve, may be provided on the outlet 28 to control the egress of the liquid from the flow cell so that the flow cell is filled with liquid. Pump 12 maybe of any suitable type. As here shown it is la proportioning pump of the type described in U.S. Patent No. 2,893,324. Briefly described, this type of pump comprises a platen 82 and the flexible pump tubes 38, 40, 46, 48 and 72 which are resiliently compressible and are all simultaneously compressed progressively along their lengths against platen 82 by transverse pressure rollers 84 carried by conveyor sprocket chains 86 which are driven by a shaft 88 actuated by a motor (not shown). Said chains 86 are carried by a frame 90 which is pivoted at 92 so that said pressure rollers can be moved to a retracted position out of engagement with the pump tubes for access to the latter when desired.

It will be understood that the apparatus may be employed for the continuous analysis of a flowing stream of a series of samples or for the analysis of a continuous liquid stream and is especially useful where the apparatus must be installed in a vehicle which may move in a plurality of directions. The apparatus is particularly useful for determining, for example, the chloride content in the boiler feed water of a steam power plant aboard a ship. For such a determination, the boiler feed water is continuously supplied as a stream to pump tube 38 and air or other suitable inert and separable fluid is supplied to pump tube 40. A 6% solution of ferrie alum FeNH4(SO4) %N HNO3 is supplied to pump tube 46 and a saturated solution of mercuric thiocyanate Hg(CNS)2 is supplied to pump tube 48. The streams of ferrie alum and mercuric thiocyanate are mixed in helical mixing coil 56 and join the segmented liquid stream of boiler feed water flowing in conduit 42. The mixed reagent joins each of the liquid segments in the segmented stream and is mixed with the boiler feed water in each liquid segment in helical mixing coil 60. The air segments in the segmented stream are removed in fitting 62 and the liquid segments are blended together in blender 76 and are transmitted, as a consolidated stream, to the flow cell 18 where `the color of the stream is measured to indicate the quantity of the chlorine present in the boiler feed water. The results of this measurement are recorded on the recorder 16 which is operated under the control of the colorimeter 14 in a well known manner.

While we have shown and described the preferred ern- `bodiments of the invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that certain changes in the form and arrangement of parts and in the specific manner of practicing the invention may ybe made without departing from the underlying ideas or principles of this invention within the scope of the appended claims.

What is claimed is:

l. In a system of liquid treatment and analysis in which the liquid is transmitted in the form of a stream and is treated while in transit for analysis, said system including tubular means through which said stream flows, means for .introducing an inert separable fluid int-o said liquid stream in said tubular means to divide said liquid stream into a segmented stream comprised of a series of liquid segments separated by intervening segments of said inert fluid; a flow cell comprising a closed tubular chamber having a peripheral wall provided with a liquid inlet to receive liquid from said tubular means and with a liquid outlet and otherwise closed to the passage of fluid, said outlet being spaced from said inlet as measured along the longitudinal axis of said chamber, said chamber comprising a hollow cylinder having opposite end walls permeable to the passage of light therethrough for the transmission of light Ithrough the liquid in said cell to colorimetrically examine the liquid in said chamber of said flow cell, said opposite end walls closing said cylinder except for said inlet and outlet, means in communication with said tubular means at a point upstream of said flow cell for removing said inert fluid segments from said segmented stream during the flow thereof and prior `to the introduction of said liquid into said flow cell, and tubular liquid blender means connected to said liquid inlet of thev flow cell and to said tubular means downstream from said point of fluid removal for blending said liquid segments together after the removal of said fluid segments to form a consolidated liquid stream which flows into said inlet of the flow cell.

2. In a system of liquid treatment and analysis in which the liquid is transmitted in the form of a stream and is treated while in transit for analysis, said system including means for introducing an inert separable fluid into said liquid stream to divide said liquid stream into a segmented stream comprised of a series of liquid segments separated by intervening segments of said inert fluid; a flow cell comprising a closed tubular chamber having a peripheral wall provided with a liquid inlet and with -a liquid outlet and otherwise closed to the passa-ge of fluid, said outlet being spaced from said inlet as measured yalong the longitudinal `axis of said chamber, said chamber comprising a hollow cylinder having end walls permeable to the passage of light therethrough for the transmission of light through the liquid in said cell to colorimetrically examine the liquid in said chamber of said flow cell, said opposite end walls closing said cylinder except for said inlet and outlet, a tubular passage for the flow of liquid to said flow cell, means for removing said inert fluid segments from said segmented stream during the flow thereof in said passage and prior to the introduction of said liquid into said flow cell, said tubular passage having an opening therein upstream of the liquid inlet of said flow for said removal of the fluid segments, and liquid blender means in said tubular passage downstream of said opening for blending said liquid segments together after the removal of said fluid segments to form a consolidated liquid stream, said liquid blender means comprising a tubular member having a series of hollow longitudinally spaced portions connected to each other by a series of intervening tubes, said portions having a different cross sectional area in the direction of flow of said liquid segments than said tubes to vary the velocity of tiow of said liquid segments through said blender means.

3. In a system of liquid treatment and analysis in which vvthe liquid is transmitted in the form of a stream and is and otherwise closed to the passage of fluid, said opposite' end walls closing said cylinder except for said inlet and outlet, said outlet being spaced from said inlet as measured along the longitudinal axis of said chamber, said chamber comprising a hollow cylinder having end walls permeable to the passage of light therethrough for the transmission of light through the liquid in said cell to colorimetrically examine the liquid in said chamber of said llow cell, a tubular passage which is in communication with said inlet of the flow cell, means for removing said inert fluid segments from said segmented stream during lthe oW thereof and prior to the introduction of said liquid into said flow cell, said tubular passage having an opening therein upstream of said inlet of the flow cell, suction means connected to said opening for aspirating said inert fluid segments from said segmented stream for said removal of the segments as said stream flows through said passage to said flow cell, and liquid blender means inserted between said tubular passage and said ow cell for blending said liquid segments ytogether after the removal of said lluid segments to form a consolidated liquid stream, said liquid blender means comprising a tubular member having a series of hollow longitudinally spaced portions connected to each other by a series of intervening tubes, said portions having a different cross sectional area in the direction of flow of said liquid segments than said tubes to vary the velocity of ow of said liquid segments through said blender means.

4. In a system of liquid treatment and analysis in which the liquid is transmitted in the form of a stream and is treated while in transit for analysis, said system including means for introducing an inert separable iluid into said liquid stream to divide said liquid stream into a segmented stream comprised of a series of liquid segments separated by intervening segments of said inert iluid; a ow cell comprising a closed tubular chamber having a peripheral wall provided with a liquid inlet and with a liquid outlet and otherwise closed to the passage of uid, said outlet being spaced from said inlet as measured along the 1ongitudinal axis of said chamber, said chamber comprising a hollow cylinder having end walls permeable to the passage of light therethrough for the transmission of light through the liquid in said cell to colorimetrically examine the liquid in said chamber of said ow cell, said opposite end walls closingsaid cylinder except for said inlet and outlet, a tubular passage in communication with said inlet of the flow cell, means for removing said inert uid segments from said segmented stream during the ow thereof and prior to the introduction of said liquid into said. iiow cell, said tubular passage having an opening therein for the exhaust of said uid segments from said passage, and liquid blender means in said tubular passage between said opening and said ilow cell for blending said liquid segments together after the removal of said fluid segments to form a consolidated liquid stream, said liquid blender means comprising a tubular member having a series of hollow spherical portions connected to each other by a series of intervening tubes, said spherical port-ions having a different cross sectional area transversely of the direction of ow of said liquid segments than said tubes to vary ythe velocity of tlow of said liquid segments through said liquid blender means.

5. ln a system of liquid treatment and analysis in which i the liquidis transmitted in the form of a stream and is treated while in transit for analysis, said system including means for introducing `an inert separable uid into said liquid stream to divide said liquid stream into a segmented stream comprised of a series of liquid segments separated by intervening segments of said inert lluid; a ow cell comprising a closed tubular chamber having la peripheral wall provided with a liquid inlet and with a liquid outlet and otherwise closed to the passage of fluid, said outlet being spaced from saidl inlet as measured along its longitudinal axis of said chamber, said chamber comprising a hollow cylinder having end walls permeable to the passage of light therethrough for the transmission of light through the liquid in said cell to colorirnetrically examine the liquid in said chamber of said ilow cell, said opposite end walls closing said cylinder except for said inlet and outlet, a tubular passage connected to the inlet of said ilow cell, means fo-r removing said inert fluid segments from said segmented stream during the ow thereof and prior to the introduction of said liquid into said flow cell, said tubular passage having an opening therein, suction means connected to said opening for aspirating said inert lluid segments from said segmented stream as said stream ows through said passage to said ow cell, and liquid blender means in said tubular passage between said opening and said ilow cell for blending said liquid segments together after the removal of said liuid segments to form a consolidated liquid stream, said liquid blender means comprising a tubular member having a series of hollow spherical portions connected to each other by -a series of intervening tubes, said spherical portions having a different cross sectional area transversely of the direction of flow of said liquid segments than said tubes to vary the velocity of ow of said liquid segments through said liquid blender means.

References Cited in the tile of this patent UNITED STATES PATENTS 1,658,950 Stein Feb. 14, 1928 2,462,995 Ritzmann Mar. 1, 1949 2,797,149 Skeggs Iune'25, 1957 2,899,280 Whitehead et -al Aug. 1l, 1959 2,967,764 Skeggs Jan. 10, 1961 2,999,673 Kessler Sept. 12, 1961 3,010,800 Whitehead etal Nov. 28, 1961 3,047,367 Kessler July 3l, 1962 

1. IN A SYSTEM OF LIQUID TREATMENT AND ANALYSIS IN WHICH THE LIQUID IS TRANSMITTED IN THE FORM OF A STREAM AND IS TREATED WHILE IN TRANSIT FOR ANALYSIS, SAIS SYSTEM INCLUDING TUBULAR MEANS THROUGH WHICH SAID STREAM FLOWS, MEANS FOR INTRODUCING AN INERT SEPARABLE FLUID INTO SAID LIQUID STREAM IN SAID TUBULAR MEANS TO DIVIDE SAID LIQUID STREAM INTO A SEGMENTED STREAM COMPRISED OF A SERIES OF LIQUID SEGMENTS SEPARATED BY INTERVENING SEGMENTSSAID INERT FLUID; A FLOW CELL COMPRISING A CLOSED TUBULAR CHAMBER HAVING A PERIPHERAL WALL PROVIDED WITH A LIQUID INLET TO RECEIVE LIQUID FROM SAID TUBULAR MEANS AND WITH A LIQUID OUTLET AND OTHERWISE CLOSED TO THE PASSAGE OF FLUID, SAID OUTLET BEING SPACED FROM SAID INLET AS MEASURED ALONG THE LONGITUDINAL AXIS OF SAID CHAMBER, SAID CHAMBER COMPRISING A HOLLOW CYLINDER HAVING OPPOSITE END WALLS PERMEABLE TO THE PASSAGE OF LIGHT THERETHROUGH FOR THE TRANSMISSION OF LIGHT THROUGH THE LIQUID IN SAID CELL TO COLORIMETRICALLY EXAMINE THE LIQUID IN SAID CHAMBER OF SAID FLOW CELL, SAID OPPOSITE END WALLS CLOSING SAID CYLINDER EXCEPT FOR SAID INLET AND OUTLET, MEANS IN COMMUNICATION WITH SAID TUBULAR MEANS AT A POINT UPSTREAM OF SAID FLOW CELL FOR REMOVING SAID INERT FLUID SEGMENTS FROM SAID SEGMENTED STREAM DURING THE FLOW THEREOF AND PRIOR TO THE INTRODUCTION OF SAID LIQUID INTO SAID FLOW CELL, AND TUBULAR LIQUID BLENDER MEANS CONNECTED TO SAID LIQUID INLET OF THE FLOW CELL AND TO SAID TUBULAR MEANS DOWNSTREAM FROM SAID POINT OF FLUID REMOVAL FOR BLENDING SAID LIQUID SEGMENTS TOGETHER AFTER THE REMOVAL OF SAID FLUID SEGMENTS TO FORM A CONSOLIDATED LIQUID STREAM WHICH FLOWS INTO SAID INLET OF THE FLOW CELL. 